1. Field of the Invention
This invention relates to a blend of fibers for use in protective clothing, a lightweight fabric made from such blend, protective articles made from the blend or fabric, and methods for making the fabric. The protective fabrics and articles of this invention have the unique combination of being comfortable, being highly effective against electrical arcs and flash fire hazards, and having a pleasing appearance. Specifically, these fabrics can be processed to give the look and feel similar to conventional clothing fabrics such as denim fabrics.
2. Description of Related Art
Several types of commercial products are used for protection against electrical arcs and flash fires. DIFCO Performance Fabrics, Inc., of Montreal, Quebec, Canada, offers for sale a dark blue fabric under the trade name of “Genesis” that is made entirely from Nomex® Type 462 staple fibers, which contain amorphous meta-aramid fibers. Southern Mills, Inc., of Union City, Ga., offers for sale solid shade spruce green protective fabrics under the trade names of “AtEase 950” and “Defender 950” that are also made entirely from Nomex® Type 462 staple fibers. These fabrics have good arc protection performance but are generally considered to not be as comfortable as traditional apparel fabrics since they are composed almost entirely of aramid fibers.
Southern Mills also offers for sale a royal blue protective fabric under the trade name of “ComfortBlend”, which is made from an intimate blend of 35 percent by weight flame retardant rayon staple fibers and 65 percent by weight Nomex® Type 462 staple fibers, which contain amorphous meta-aramid fibers. The addition of the flame retardant rayon increases the comfort of this fabric at the expense of arc protection performance.
Workrite Uniform Company of Oxford, Calif., offers for sale a garment (Style #410-NMX-85-DN), described as a “denim jean cut pant”. This garment is believed to be made from a fabric having Nomex® Type N-302 staple fibers (which contains crystallized meta-aramid fibers) in the warp direction of the fabric; and Nomex® Type T462 staple fibers (which contains amorphous meta-aramid fibers) in the fill direction. This fabric, while having good arc protection performance, does not have a pleasing appearance, and is generally not very comfortable since it is composed almost entirely of aramid fibers.
It is well known that aramid fabrics are more difficult to dye than traditional apparel fabrics, and the percent crystallinity of aramid fiber dramatically affects the degree to which the fiber may be dyed. The higher the crystallinity of the aramid fiber, the harder it is to dye. It is especially difficult to give such aramid fabrics the general appearance of a cotton denim fabric due to the differences in aramid fiber crystallinity. The simple addition of cotton, by blending cotton fiber with the meta-aramid fiber, does not provide a suitable solution to this problem. Cotton must be chemically treated to make it flame retardant. This is done in fabric form, which stiffens and reduces the suppleness of the fabric. This makes any protective apparel made from this fabric less comfortable than apparel made from the untreated fabric.
What is needed is a fabric that not only has good electrical arc and flash fire performance but that also has the look and feel that approaches that of traditional fabrics like denim fabric.